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Psoriatic Arthritis in Children

What is psoriatic arthritis?

Psoriatic arthritis is a form of arthritis associated with psoriasis, a chronic skin and nail disease characterized by red, scaly rashes and thick, pitted fingernails. The disease is similar to rheumatoid arthritis in symptoms, characterized by joint inflammation. However, psoriatic arthritis tends to affect fewer joints than rheumatoid arthritis and does not produce the typical rheumatoid arthritis antibodies. The arthritis associated with psoriatic arthritis comes in five forms:

Arthritis that affects the small joints in the fingers and/or toes

Asymmetrical arthritis of the joints in the extremities

Symmetrical polyarthritis, a type of arthritis similar to rheumatoid arthritis

Arthritis mutilans, a rare type of arthritis that destroys and deforms joints

Psoriatic spondylitis, arthritis of the sacroiliac sac (in the lower back) and the spine

Psoriatic arthritis is one of four disorders which are classified as spondyloarthropathies. The other disorders are juvenile ankylosing spondylitis, inflammatory bowel disease, and Reiter's syndrome. These disorders have similar features such as:

Inflammation of the spine and sacroiliac joints

Family history of the disease

Similar nonarthritis symptoms

Absence of rheumatoid factor in the blood (an antibody found in the blood of most, but not all, people who have rheumatoid arthritis, as well as other rheumatic diseases)

What causes psoriatic arthritis?

Although the cause of psoriatic arthritis is unknown, factors such as immunity, genetics, and the environment may play a role.

What are the symptoms of psoriatic arthritis?

The skin condition, psoriasis, may actually precede or follow psoriatic arthritis. The following are the most common symptoms of psoriatic arthritis. However, each child may experience symptoms differently. Symptoms may include:

Inflamed, swollen, and painful joints, usually in the fingers and toes

Morning stiffness

Reddened skin over the infected joint(s)

Deformed joints from chronic inflammation

Pitting of fingernails or toenails

Eye pain

Fatigue

As stated above, psoriasis may occur either before or after the onset of psoriatic arthritis. Some symptoms of psoriasis may include a scaly, pinkish-red, itchy rash on the knees, elbows, scalp, face, and folds of the buttocks.

Symptoms of psoriatic arthritis may resemble other medical conditions or problems. Always consult your child's doctor for a diagnosis.

How is psoriatic arthritis diagnosed?

If psoriasis has been diagnosed before or at the time the other symptoms of psoriatic arthritis are found, a diagnosis of psoriatic arthritis may be easily confirmed. However, when psoriatic arthritis symptoms precede symptoms of psoriasis, diagnosis is more difficult. Although psoriatic arthritis sometimes causes an elevated erythrocyte sedimentation rate, mild anemia, and elevated blood uric acid levels, these symptoms are also associated with other rheumatic diseases, including gout.